Yellowstone Volcano Observatory Monthly Update: October 1, 2019

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Mike Poland, Scientist-in-Charge of the Yellowstone Volcano Observatory, describes activity at Yellowstone during the month of September 2019.
 

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Image Dimensions: 1920 x 1080

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Length: 00:06:52

Location Taken: US

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Video edited by Liz Westby
 

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- Hi everybody, I'm Mike Poland, the Scientist-in-Charge of the Yellowstone Volcano Observatory and I'm coming to you today from the Upper Geyser Basin in Yellowstone National Park with the activity update for October of 2019. I thought this would be a fun place to do the update because it's an anniversary of sorts. You might remember in mid to late September of 2018, there was a rare eruption of Ear Spring, that's the pool that's right here next to me. It hadn't erupted in a few decades and when it did erupt, it destroyed the sort of pristine area and littered rocks all around this area. The rocks that you see here. But in addition to bringing up a bunch of rocks, it also brought up a bunch of human garbage, coins, a cinder block, a pacifier, aluminum cans with pull tabs so it clearly had been a while since it erupted. So it's really a pretty extraordinary event and a great example of the dynamic nature of the geyser system in Yellowstone. The one constant here is change. It's always changing. Okay, well let's get to the activity report and talk about what happened in September of 2019 in Yellowstone. It was a pretty quiet month for earthquakes in the Yellowstone region. The University of Utah seismograph stations which is responsible for the operation and analysis of the Yellowstone seismic network located only 71 earthquakes in the region during the month of September. The largest was this micro earthquake here, south of West Yellowstone. It was only a magnitude 2.4 and that occurred on September 8th. And there was no swarm activity detected during the month. Now this is a bit below average for the region. Typically we expect to see about 1,500 to 2,000 earthquakes a year that are located by University of Utah. This year however, we're not quite up to 1,000 so earthquake activity for the year has been a bit subdued. In terms of deformation, I'd like to show some additional plots this month. This is from the White Lake GPS Station, which is located on the Sour Creek Resurgent Dome. I've got the east component here. The north component here and the vertical down here. The east component, whenever that has a positive trend, that means the station's moving east and negative means it moving west. A positive in the north component means the station's moving north and a negative trend means it's moving south. And of course for the vertical component, if there's a negative trend, it means subsidence and if there's an upward component, it means uplift. You can see right here, right about mid-September, there's an offset, especially in the east and the north components. And this is because UNAVCO, which does all the maintenance on GPS stations in addition to strainmeters and tote meters in the park, went and did some maintenance on the GPS network and they replaced the GPS antenna here at White Lake and that resulted in this offset because the antenna wasn't quite in the exact east and north location as it was before. So this offset is not a real offset because of any motion, it's because the antenna had been changed. There may also be a slight change in the vertical component although it's obviously much, much smaller than the offset we saw in the east and north. Now overall it seems like there might be a bit of a change in deformation at this station in terms of the uplift. We had been seeing subsidence that had actually been going on with little interruptions here and there since 2015. Throughout the summer of 2019, it looked like there might be a bit of uplift although we've seen seasonal things like this in the past and now we might be switching back to, at least rolling over into perhaps back to this subsidence. So it looks like no major changes overall in the trends on the Sour Lake GPS Station. This is the Old Faithful GPS Station on the Mallard Lake Resurgent Dome, the same as we saw earlier, east, north and up and there are these offsets again because the antenna was replaced by the UNAVCO engineers in the middle of September. And we have the same sort of pattern of this summer of 2019 apparent uplift which may be just a seasonal change interrupting this overall slight trend of subsidence. And we may be rolling back over now and going back into subsidence now that the summer in Yellowstone is over. And finally there is the site that's overlooking the Norris Geyser Basin and our WY, east north and up. Again the GPS antenna was replaced so we see these large offsets in east and north. It doesn't have much of an effect on the vertical component where after uplift that had been occurring since 2015, we've now had a year of very little change in the Norris area. Starting in October of 2018, that uplift seems to have paused and that pause has continued today. In fact, we may even see a slight amount, maybe about a centimeter of subsidence at Norris over the past year so not a lot of deformation in the Norris area overall. And then finally to everyone's favorite geyser, Steamboat. Just to keep you updated on what's happening there. This is the temperature record from the steamboat drainage channel and what you can see here are these variations, spiky sort of behavior, are due to minor eruptions that culminate in a major eruption and then as the minor eruptions and major eruptions are all over, we go back to basically sensing just air temperature and these are daily variations in air temperature. After a few days of not much activity from Steamboat, this spiky behavior steps up again, that's a lot of minor activity and culminates in a major eruption and then everything dries up again and we go back to air temperatures and we see that pattern repeated with the major eruptions generally having bigger spikes in temperature. So this reflects eruptions on September 3rd, September 11th, September 17th right here and September 25th. And you can see as we end the month of September, we're going back into that minor activity which probably will culminate in another Steamboat eruption in the coming hours to days. Sometime certainly in early October, just keeping that pattern alive. So far Steamboat has had 37 eruptions in 2019, certainly shattering the record it set in 2018 of 32 eruptions. You can always come to the Yellowstone Volcano Observatory website if you'd like more information. This is the YVO site here. It covers all the volcanoes of the American Southwest and Wyoming. For Yellowstone information specifically, go down to this high threat potential here and click on "Yellowstone". This will take you to our main Yellowstone page where you can access Caldera Chronicles which is our weekly blog all about some aspect of Yellowstone history, geology or current activity. Our monitoring page which has links to all of the monitoring data collected in the area and current alerts which give you the monthly update and any new information as needed. That does it for the activity report for October of 2019. If you have any questions, you can always email us at yvowebteam, all one word, @usgs.gov. Thanks for tuning in. Have a great October and we'll see ya in November. Bye.